CN210781339U - MEMS microphone of anti strong air current and high acoustic pressure - Google Patents

Abstract

The utility model relates to a microphone field especially relates to a MEMS microphone of anti strong air current and high acoustic pressure contains pad PCB board and MEMS microphone, be fixed with the shell on the pad PCB board, be fixed with the MEMS microphone on the inside pad PCB board of shell, the MEMS microphone contains fixes the ASIC chip on pad PCB board, the ASIC chip is connected with the MEMS chip through the bonding line, the ASIC chip is still through bonding line connection pad PCB board, be equipped with the sound hole that runs through the shell on the shell, sound hole position department is fixed with current limiting device on the shell, current limiting device contains the base with shell reciprocal anchorage, be fixed with on the base and run through the base and with the circular port that the cooperation of sound hole was used, circular port position slope is fixed with a plurality of lamellate blades on the base, lamella blade evenly distributed is on the base. The device can greatly reduce the external severe environment, strong airflow and high sound pressure impact damage to the microphone, and has excellent protection effect on the microphone.

Description

MEMS microphone of anti strong air current and high acoustic pressure

[ technical field ] A method for producing a semiconductor device

The invention relates to the field of microphones, in particular to an MEMS (micro-electromechanical systems) microphone with strong airflow resistance and high sound pressure.

[ background of the invention ]

MEMS is a Micro-Electro mechanical System (Micro-Electro mechanical System), which refers to a sensor device with a size of several millimeters or less, and the internal structure of the sensor device is generally in the micrometer or nanometer level, and the sensor device is an independent intelligent System. Briefly, the MEMS is a silicon-based sensor formed by miniaturizing mechanical components of a conventional sensor, fixing a device on a silicon wafer (wafer) by a three-dimensional stacking technique, for example, a three-dimensional through-silicon via (TSV) technique, and finally cutting and assembling the device in a specially-customized packaging form according to different application occasions. The MEMS has the advantages of miniaturization and high integration degree which cannot be achieved by the common sensor simultaneously due to the cost advantage brought by the IC silicon chip processing batch production which cannot be achieved by the common sensor.

The MEMS microphone relates to the field of semiconductor packaging, a bare chip is packaged in a container to realize the function of shape and shadow, and the difference between the MEMS microphone and other semiconductor packaging is that a Sensor chip of the MEMS microphone is a gas (sound pressure) sensitive element, and due to the reasons of material and thickness, the Sensor area of the MEMS chip is very fragile, under strong airflow and high sound pressure impact, a diaphragm has a risk of damage, the phenomenon is difficult to avoid in the actual use environment, and therefore the MEMS microphone with common packaging has the risk of high sound pressure or strong airflow impact failure.

The invention is provided for overcoming the defects of the prior art.

[ summary of the invention ]

The present invention is directed to overcoming the above-mentioned drawbacks of the prior art and providing a MEMS microphone with high airflow resistance and high sound pressure, which can effectively avoid the failure due to high sound pressure or impact of strong airflow.

The invention can be realized by the following technical scheme:

the utility model provides a MEMS microphone of anti strong air current and high acoustic pressure, contains pad PCB board and MEMS microphone, be fixed with the shell on the pad PCB board, be fixed with the MEMS microphone on the inside pad PCB board of shell, the MEMS microphone contains fixes the ASIC chip on pad PCB board, the ASIC chip is connected with the MEMS chip through the bonding wire, the ASIC chip still connects pad PCB board through the bonding wire, be equipped with the sound hole that runs through the shell on the shell, sound hole position department is fixed with current limiting device on the shell, current limiting device contains the base with shell reciprocal anchorage, be fixed with on the base and run through the base and with the circular port that the sound hole cooperation was used, circular hole position slope is fixed with a plurality of lamellate blades on the base, lamella blade evenly distributed is on the base. Through the fixed current limiting device of sound hole position department on the shell, inside sound signal can enter into the casing from the circular port of current limiting device the clearance department between the lamella form blade, and act on the vibrating diaphragm of MEMS chip, thereby realize sound signal's pick up and conversion process, can reduce the inside air current size that gets into the MEMS microphone under strong air current strikes through current limiting device, same the device also can be through the mode decay high-sound pressure sound signal of aperture shrink, when external air current is too big or the acoustic pressure is too high, the lamella form blade can be laminated together under the acoustic pressure effect, the laminating degree can change according to concrete acoustic pressure value, thereby realize reducing the inside air current size that gets into the MEMS microphone and decay and get into MEMS chip position high-sound pressure sound signal.

A production method of an MEMS microphone with strong airflow resistance and high sound pressure comprises the following steps

a. Attaching an ASIC chip on a pad PCB by using an adhesive, and curing by baking;

b. the MEMS chip is attached to the bonding pad PCB through an adhesive, and the bottom of the MEMS chip is completely sealed through the adhesive;

c. the MEMS chip, the ASIC chip and the pad PCB are electrically connected by using a bonding wire in a lead bonding mode;

d. bonding the housing and the pad PCB together using an adhesive, the adhesive layer being completely sealed;

f. the flow-limiting device is secured to the housing using an adhesive and cured by baking.

Compared with the prior art, the invention has the following advantages:

1. the device can greatly reduce the external severe environment, strong airflow and high sound pressure impact damage to the microphone, and has excellent protection effect on the microphone.

2. When external airflow is too large or sound pressure is too high, the petal-shaped blades can be attached together under the action of sound pressure, and the attachment degree can be changed according to a specific sound pressure value, so that the size of the airflow entering the interior of the MEMS microphone is reduced, and the high-sound-pressure sound signals entering the position of the MEMS chip are attenuated.

3. The device can be used in some extreme environments, such as windy weather, or occasions with high sound pressure, such as airports and the like.

[ description of the drawings ]

The following detailed description of embodiments of the invention is provided in conjunction with the appended drawings, in which:

FIG. 1 is a schematic view of a current limiting device under normal acoustic pressure;

FIG. 2 is a schematic view of the construction of a flow restriction device under high airflow or high acoustic pressure impact;

FIG. 3 is a top view of the flow limiting device under normal acoustic pressure;

FIG. 4 is a top view of a flow restriction device under high airflow or high acoustic pressure impact;

FIG. 5 is a top view of the present invention;

FIG. 6 is a schematic structural view of the present invention;

FIG. 7 is a schematic view of a current limiting device according to the present invention;

FIG. 8 is a schematic structural diagram of a MEMS chip of the present invention;

FIG. 9 is a schematic view of an assembly structure of a current limiting device and a housing according to the present invention;

in the figure: 1. a pad PCB board; 2. a housing; 3. an ASIC chip; 4. an MEMS chip; 401. a back electrode; 402. silicon-based; 403. vibrating diaphragm; 5. a bonding wire; 6. a current limiting device; 61. a base; 62. a circular hole; 63. a petal-shaped blade;

[ detailed description ] embodiments

The embodiments of the present invention will be described in detail below with reference to the accompanying drawings:

as shown in fig. 1 to 9, an anti-strong airflow and high sound pressure MEMS microphone includes a pad PCB 1 and a MEMS microphone, a housing 2 is fixed on the pad PCB 1, the MEMS microphone is fixed on the pad PCB 1 inside the housing 2, the MEMS microphone includes an ASIC chip 3 fixed on the pad PCB 1, the ASIC chip 3 is connected with a MEMS chip 4 through a bonding wire 5, the ASIC chip 3 is further connected with the pad PCB 1 through the bonding wire 5, a sound hole penetrating the housing 2 is formed in the housing 2, a current limiting device 6 is fixed at a position of the sound hole in the housing 2, the current limiting device 6 includes a base 61 fixed to the housing 2, a circular hole 62 penetrating the base 61 and used in cooperation with the sound hole is fixed on the base 61, a plurality of flap-shaped blades 63 are obliquely fixed at positions of the circular hole 62 in the base 61, and the flap-shaped blades 63 are uniformly distributed on the base 61. Through fixing current limiting device 6 in shell 2 sound hole position department, sound signal can enter into inside the casing from the clearance department between lamella form blade 63 on current limiting device 6's circular port 62, and act on MEMS chip 4's vibrating diaphragm 403, thereby realize sound signal's pick-up and conversion process, can reduce the inside air current size of entering MEMS microphone under strong air current strikes through current limiting device 6, the same device also can attenuate high-sound pressure sound signal through the mode of aperture shrink, when the external air current is too big or the acoustic pressure is too high, lamella form blade 63 can laminate together under the acoustic pressure effect, the laminating degree can change according to concrete acoustic pressure value, thereby realize reducing the inside air current size of entering MEMS microphone and attenuate and enter into MEMS chip 4 position high-sound pressure sound signal.

A production method of an MEMS microphone with strong airflow resistance and high sound pressure comprises the following steps

a. The ASIC chip 3 is attached on the welding disc PCB board 1 by using an adhesive and is cured by baking;

b. the MEMS chip 4 is attached to the bonding pad PCB board 1 through an adhesive, and the bottom of the MEMS chip 4 is completely sealed through the adhesive;

c. the MEMS chip 4, the ASIC chip 3 and the pad PCB board 1 are electrically connected by using a bonding wire 5 in a lead bonding mode;

d. bonding the case 2 and the land PCB board 1 together using an adhesive, the adhesive layer being completely sealed;

f. the flow restriction device 6 is fixed to the housing 2 using an adhesive and cured by baking.

As shown in fig. 1 to 4, when the external airflow is too large or the sound pressure is too high, the flap-shaped blades 63 will be attached together under the action of the sound pressure, and the attachment degree will change according to the specific sound pressure value, as shown in fig. 2 and 4, which are schematic diagrams of the yield degree of the flap-shaped blades 63 in the state of high sound pressure or strong airflow; under normal conditions, the sound hole diameter D0, the vertical height H0 of the petal-shaped vanes 63, the sound hole diameter D1 and the vertical height H1 of the petal-shaped vanes 63 under strong airflow or high sound pressure impact, wherein D0 > D1 and H0 > H1, and under strong airflow or high sound pressure impact, the gaps of the petal-shaped vanes 63 become smaller, namely the sound entering area is reduced.

As shown in fig. 8, the structure of the MEMS chip 4 is shown, the MEMS chip 4 is composed of a diaphragm 403, a back electrode 401 and a silicon substrate 402, the diaphragm 403 and the back electrode 401 are fixed inside the cavity of the silicon substrate 402 by a semiconductor processing technology (etching, polishing, evaporation, etc.), the operation principle of the MEMS chip is equivalent to a parallel plate capacitor, the diaphragm 403 and the back electrode 401 constitute the upper and lower substrates of the capacitor, charges directionally move under the action of voltage, a stable voltage difference is formed between the upper and lower substrates, when external sound pressure acts on the diaphragm 403, the distance between the diaphragm 403 and the back electrode 401 changes, the formula C ∈ S/4 π kd shows that the capacitance of the capacitor changes when the distance changes (C: capacitance ∈ dielectric constant, S: the facing area d between the diaphragm 403 and the back electrode, k: constant between the two plates), U ═ Q/C shows that the output voltage value changes when the distance changes (Q is the charge amount of the capacitor, Q is the constant, the charge amount of the diaphragm 403 remains unchanged, k: constant electrostatic force between the two plates 401), U ═ Q/C, when the capacitance changes, the output voltage of the MEMS chip is 364, the voltage after the change, the output voltage of the MEMS chip is 3632, the voltage after the mechanical sound pressure changes, the MEMS chip is changed, U — 3632, the voltage after the action of the MEMS chip is changed, the output voltage of the MEMS chip.

The above description is only a preferred embodiment of the present invention, and it should be noted that a person skilled in the art can make various changes, modifications, substitutions and alterations to the embodiments without departing from the technical principles of the present invention, and such changes, modifications, substitutions and alterations should also be regarded as the protection scope of the present invention.

Claims (1)

1. The utility model provides an anti strong air current and high acoustic pressure's MEMS microphone which characterized in that: contain pad PCB board and MEMS microphone, be fixed with the shell on the pad PCB board, be fixed with the MEMS microphone on the inside pad PCB board of shell, the MEMS microphone includes fixes the ASIC chip on the pad PCB board, the ASIC chip is connected with the MEMS chip through the bonding wire, the ASIC chip still connects pad PCB board through the bonding wire, be equipped with the sound hole that runs through the shell on the shell, sound hole position department is fixed with current limiting device on the shell, current limiting device contains the base of mutually fixing with the shell, be fixed with on the base and run through the base and with the circular port that the cooperation of sound hole was used, circular hole position slope is fixed with a plurality of lamellate blades on the base, lamella blade evenly distributed is on the base.

Images